1. Field of the Invention
The present invention relates, in general, to improving sealing performance of a door for changing over an air passage through which the air flows, such as a door for changing over the air passage of an air conditioner for vehicles.
2. Description of the Related Art
A door for changing over the air passage used in an air conditioner for vehicles has been taught in Japanese Unexamined Patent Publication (Kokai) No. 11-180129. According to the publication a sealing member made of a rubbery elastic material is provided along the outer peripheral edge portion of a door plate, and the sealing member is elastically pressed onto the sealing surface on the side of the air passage to accomplish a sealing effect.
The sealing member made of a rubbery elastic material usually has the shape of a flat plate (single lip shape) as shown in FIGS. 22A to 22C from the standpoint of easy molding. In FIGS. 22A to 22C, reference numeral 10 denotes a door plate, 11 denotes a sealing member, 12 denotes a casing of the air passage, and 12a denotes a sealing surface thereof.
In the door for changing over the air passage provided with the sealing member 11 of the shape of a flat plate, a gap is formed between the sealing member 11 and the sealing surface 12a and the air leaks as shown in FIG. 22c when the door plate 10 and the sealing member 11 undergo elastic deformation in a direction away from the sealing surface 12a on the side of the air passage upon receiving air pressure (arrow A) in the air passage.
It can therefore be contrived to form the sealing member 11 to have a folded shape in cross section as shown in FIGS. 23A and 23B or to possess a V-shape in cross section as shown in FIGS. 24A and 24B in order to increase the amount of elastic compression of the sealing member 11 in a state where the sealing member 11 is pressed onto the sealing surface 12a. Even by employing the above folded shape or the V-shape, however, the door as a whole undergoes an elastic deformation in a direction away from the sealing surface 12a when it receives the wind pressure, again forming a gap and making it difficult to maintain the sealing performance to a sufficient degree.
Referring to FIG. 25A, further, it can be contrived to form the sealing member 11 in a double U-shape in cross section. When the door as a whole receives the wind pressure from a direction of arrow A as shown in FIG. 25B, the inside of the U-shaped portion of the sealing member 11 that has the double U-shape in cross section receives a force in the direction of arrow B (direction opposite to the arrow A), and the outer side of the U-shaped portion of the T-shaped sealing member 11 tends to be pressed onto the sealing surface 12a due to the force in the direction of the arrow B. Therefore, the sealing member having a cross sectional shape as shown in FIG. 25A is superior to the sealing members having cross sectional shapes as shown in FIGS. 22A to 24B with regard to the sealing performance.
Even with the sealing member shown in FIG. 25A, however, the support portion of the sealing member 11 is protruding by a predetermined length L in the same direction as the door plate 10 from the end surface of the outer peripheral edge of the door plate 10. When the door is closed, therefore, the sealing member 11 is deformed in a direction opposite to the sealing surface 12a. Further, when the sealing member 11 receives the wind pressure, the support portion of the predetermined length L is deformed toward the side opposite to the sealing surface as shown in FIG. 25B. This decreases the amount of elastic compression of the sealing member 11 to deteriorate the sealing performance.
In view of the above-mentioned problems, it is an object of the present invention to provide a door, for changing over an air passage, having a sealing member made of an elastic material provided along the outer peripheral edge of the door plate, in order to suppress a decrease in sealing performance due to wind pressure.
In order to accomplish the above object, according to one aspect of the present invention;
a sealing member (11) made of an elastic material secured to the outer peripheral edge of a door plate (10) is provided with support portions (11a, 11b, 11g) that extend in a direction to intersect the door plate (10), the support portions (11a, 11b, 11g) being directly supported by the outer peripheral edge of the door plate (10);
sealing portions (11c, 11d) pressed onto a sealing surface (12a) of an air passage casing (12) are so formed as to be directed toward the central portion of the door from the support portions (11a, 11b, 11g); and
the sealing member (11) is folded, in cross-section, from the outer peripheral edge of the door plate (10) toward the central portion of the door due to the support portions (11a, 11b, 11g) and the sealing portions (11c, 11d).
Thus, the sealing member (11) is folded, in cross-section, from the outer peripheral edge of the door plate (10) toward the central portion of the door. Accordingly, the wind pressure acts in a direction to expand the U-shaped portion on the inside of the sealing portions (11c, 11d)(in a direction in which the sealing portion is pressed onto the sealing surface).
Besides, the support portions (11a, 11b, 11g) extending in the direction to intersect the door plate (10) are directly supported by the outer peripheral edge of the door plate (10). Therefore, the sealing member (11) is firmly supported by the highly rigid door plate (10), and is not entirely deformed in the lee side despite of receiving the wind pressure.
Thus, the effect of the wind pressure is overcome, and the sealing performance is favorably maintained by the door for changing over the air passage.
According to another aspect of the present invention, there is provided a door for changing over the air passage, comprising a butterfly door (D1) having a rotary shaft (13) arranged at the central portion of a door plate (10), wherein:
sealing members (11, 11xe2x80x2) made of an elastic material are secured to the outer peripheral edges on one side and on the other side of said door plate (10) with said rotary shaft (13) as a boundary;
the sealing member (11) on one side of said door plate (10) is arranged on the lee side of a sealing surface (12a) of an air passage casing (12), and the sealing member (11xe2x80x2) on the other side of the door plate (10) is arranged on the windward side of the sealing surface (12a) of said air passage casing (12); and
the sealing member (11) on said one side is folded so as to be pressed onto said sealing surface (12a) by the wind pressure, and said sealing member (11xe2x80x2) on the other side of said door plate (10) is formed in the shape of a flat plate so as to be pressed onto said sealing surface (12a) by the wind pressure.
In the butterfly door (D1) which rotates about the rotary shaft (13) at the central portion of the door plate (10), the sealing member (11) on one side located on the lee side of the sealing surface (12a) is folded and exhibits a favorable sealing function by utilizing the wind pressure. The sealing member (11xe2x80x2) on the other side is located on the windward side of the sealing surface (12a), and exhibits a favorable sealing function though it has the shape of a flat plate.
According to a further aspect of the present invention, there is provided an air conditioner for a vehicle having an internal air/external air change-over door (23) for opening and closing an internal air intake port (21) and an external air intake port (22); wherein said internal air/external air change-over door (23) has door plates (23a, 23b) and sealing members (28, 29) made of an elastic material secured to the outer peripheral edges of the door plates (23a, 23b);
said sealing members (28, 29) are pressed onto sealing surfaces (30 to 33) of said internal air intake port (21) and of said external air intake port (22); and
said sealing members (28, 29) are further folded so as to be pressed onto said sealing surfaces (30 to 33) by the wind pressure of the external air from said external air intake port (22).
By using the internal air/external air change-over door (23), therefore, the sealing members (28, 29) are pressed onto the sealing surfaces (30 to 33) by the wind pressure of the external air, to obtain a favorable sealing function by utilizing the wind pressure.
Reference numerals in parentheses attached to means designate correspondence to concrete means appearing later in the description of the embodiments.
The present invention may be more fully understood from the description of the preferred embodiments of the invention, as set forth below, together with the accompanying drawings.